Method of making skid-resistant tire



Dec. 18, 1956 F. o. SKIDMORE METHOD OF MAKING SKIDRESISTANT TIRE 2Sheets-Sheet 1 Filed Dec. 31, 1952 INVENTOR Frank 8. Skidmore $714182?ATTORNEYS Dec. 18, 3956 F. o. SKIDMORE METHOD OF MAKING SKID-RESISTANTTIRE 2 Sheets-Sheet 2 Filed Dec; 31, 1952 INVENTQR 'Franlr Q, Skidmzw'eATTORNEYS U ed ms Patt Q 2,774,409 METHOD OF MAKING SKID-RESISTANT TIREApplication December 31, 1952, Serial Nb. 328,847

7 Claims. (Cl. 154-14 This invention relates to a pneumatic tire and toa process of manufacturing the same. In particular, it relates to apneumatic tire provided with a fabric tread surface having unusualtraction and skid-resistant characteristics.

One object of the subject invention is to provide a pneumatic tire whichis both skid-resistant and longwearing.

Another object of the subject invention is to provide a pneumatic tirewhich is skid-resistant and which is relatively simple and inexpensiveto make.

Other objects and advantages will become apparent from examination ofthe drawings in which like numerals relate to like parts throughout. Inthe drawings:

Figure 1 is a perspective view of a pneumatic tire with the treadportions buffed smooth;

' Fig.2 is a sectional view taken along line 2'2 of Figure 1 showing thecross-sectional shape of a buffed tire and showing in phantom lines theworn-E and buifed-off tread portion;

Fig. 3 is a sectional view of the crown portion cut from a tirebuffed-01f to provide an even tread and fabric thickness and showing inphantom lines the worn-01f and buffed-0E tread portion;

Fig. 4 is a sectional view of the cut-out crown portio of Fig. 3turnedinside out; i V Fig. 5 is a sectional view showing the inside-outcrown portion of Fig. 4 assembled on the tread of a buffed tire; Fig. 6shows the assembly of Fig; 5 placed in a retread mold for vulcanization;

Fig. 7 is a cross-sectional view of a pneumatic tire of the subjectinvention with the cut-out crown portion vulcanized thereon; i i

' Fig. 8'is a cross-sectional view showing a form ofvulcanizationapparatus provided with built-in heating elements;

Fig. 9 is a cross-sectional view of the crown portion of a modified formof a tireof the subject invention;

Fig. 10 is a perspective view of a section of a tire of thesubjectinvention provided with tread configurations; and i Fig. 11 is aperspective view of a section of another modified form of fife inaccordance with the subject invention provided with cemented-on fabrictreadportions.

The subject invention relates both to a process of retreading apneumatic tire to make it skid-resistant and #5 t ni tastu ia s qrda qwith i P e It involvesthe steps of buffing thetreadofi a tire, cuttingwt nsi st i aathehufiqdrq qw P n, t m n the crown portion inside out andassembling it on a second bufied-off tire carcass. This forms apneumatic tire with a fabric tread portion or road contacting portion.The fabric tread portion surprisingly has great traction andskid-resistance and is relatively long wearing.

A bufied-ofi tire I is shown in Fig. l. The tire can be buifed-ofi andthe tread removed in accordance with '2 any of the recognized processes.This generally involves grinding and otherwise removing the worn treadportion from the tire until a clean, slightly roughened surface ispresented. Old and scrap (tires are generally utilized for this purposebecause they are the least expensive. The tire casing should becarefully inspected, however, to make sure that it is unbroken and ingood condition.

Fig. 2 shows a cross-sectional view of the bufied tire of Figure 1withthe tread portion 2, which has been removed by wear and bufiing,being shown in phantom outline. Since a used tire is generally employedand is less expensive, much of the tread portion will have been worn otfin service and it will only be necessary to buif off a small portion ofthe tread in order to provide a clean buffed surface. The tire I ispreferably buffed to a slightly rounded section as shown in Fig. 2.

In order to obtain the crown portion of fabric cap 4 of Figs. 3 and 4, atire is buffed to substantially even thickness and cut along lines 15around the periphery on both sides. The bufied-ofi tread portion 5 isshown in phantom outline. The tire used for this purpose may even be onewhich is a scrap tire and is unfit for retreading, such as one withcasing damage. The cuts 15 can be located at various points along thecrown portion of tire depending upon theiwidth of the tire beingretreaded and of fabric tread desired. Thus if a small passenger tire isbeing retreaded a crown portion may be cut out of a large truck tire tohave approximately the same width as that of the passenger tire.

The crown portion 4 cut out of the tire is shown in Figs. 3 and 4. Itshould be noted that in Fig. '3 the fabric 7 of the tire casing isinnermost and the remaining tread rubber 6 is outer most; The crownportion or fabric tread ring 4 is in the form of an annulus or ring. InFig. 4 the crown portion has been turned inside out or reversed to placethe fabric 7 on the periphery and the remaining tread rubber 6 on theinside.-

After the crown portion has been formed as noted above, the buffedsurface oftire carcass 1 or the tire to be retreaded 1' is then coveredwith' a thin layer of gum cement and an uncured cushion stock or gumstock 8 is placed around the tread peripher'yover the cement and againstthe tire crown. It is important that the tread be evenly buffed olf toleave'a clean surface and that the tire casing be'in good condition.'The ends of the stock are carefully matched up and bubbles re moved. Alayer of cement is then applied over the inside of crown portion 4 andthe crown portion in over'the tire and against the uncured stock asshown in Fig. 5. In this latteroperation it maybe necessary to spreadthe tire beads apart in order to collapse the the crown portion 9 andprovide room for the cut-outcrown portion or fabric cap 4. An assemblyis thus formed With uncured gum stock 8 disposed between the fabric capand tire carcass crown portion or treadportion and with cement disposedon both sides of thegum stock.

' Thisassembly is then placed on a rim 18 in ring 11 and 7 plates 12 and13 fit on either side thereof and are bolted together with bolt 16 andnut 14." Air bag 17 is placed inside the tire and blown up to-expand thetire f'and fabric cap against the ring 11. The plates are boltedtogether so as to subject the side walls of the tire, to pressure andfurther force the tire crown 9 outward against ring 11. The tireassemblyinthis retread mama is then placed in'a furnaceand subjected toheat until it' has vulcanized. After suitable vulcanization, the mold isdisassembled and the tire removed.

The completed tire 19 as taken from the mold is shown in Fig. 7. Thistire has an outer layer of fabric 7 which acts as a tread. The fabriclayer is relatively thick and is found to wear very well and to provideunusual skid-resistant characteristics.

saidmold.

,, 4. A process of metreading' a tire comprising the steps 7 ofbuffingofithe tread of said tire to formabufied Fig. .8 showsanalternative form of retread mold 25. This mold is provided with aU-shaped cover 21 and crown of substantially uniform width,,bufling offthe inner ring 24. Mounted onring 24 are electrical heating.

elements 23.. .The inner surface ofcover 21-is provided with insulation22. This mold provides its own vulcanizationlheatand does not have tobeput in a furnace; Fig.9. shows a modification of'thesubject inventionin whichathe tread is completelybuffed off the scrap tire .and 'a:fabn'ccap 27 thus formed is applied to the retread tiref This'tire 26 thuscomprises a fabric tread 27 and a crown portion 28 joined by gum stocklayer2l Fig; 10 shows a tire 31 similar to the tire of Fig. 7; exceptthatgrooves 33 have been cut into the fabric cap Mportion 34 onlcarcasscrown 36 to provide tread con: 'figurations or'tread portions 32. Y Thegrooves are generally cut into and through the fabric layer so that onlythe top of the tread configurations 32 has fabriclthereon.

The grooves canbe easily formed by cutting the tire fabric along thebias and ripping it out. V

' 'Fig. 11 shows still another modification of the subject invention inwhich'layer of uncured rubber 38 is applied to the crown of a'buifedtire and strips of fabric 39 are cemented to uncured rubber layer 38 toprovide individual tread configurations. The effect of this tread is psimilarto-thatof Fig. 10.

I The fabric caps shown have been made from tire casings and. generallycomprise three or more layers of fabric with the biasset at variousangles to'the adjacent layer.

Tire casing fabric is readily available and inexpensive; Tire casingswith cotton, nylon, and rayon Hfibersare substantially equivalent forthis use. 'It is understood that other cloth fabric 'and mat ofsubstantial thickness can also' beemployed in accordance withthisinventiong V Although several embodiments of the subject inventionhave been herein shown and described, it will be understood that inaccordance with the provisions of the patent statutes, numerousmodifications of the construction shown may be resorted to withoutdeparting from'the' spirit of this invention.

' What I claim is:

1 1. A process'of retreading a tire comprising the steps of; buffing offIhetread of a tire, cutting the bufied 'crown oif at the shoulders toform a'fabric portion," 1 turning said fabric portion insideout,,bufiing,oif the tread -of,a secoind tire, assembling saidinside-out fabric portion over the buffed crown of said second tire withuncured stool; and cement disposed 3 between the crown i'of said secondtire and said fabric portion, and

r said gum stock, to bond permanently said fabric portion tothe'assembled tire.

2.;,The methodof claim l in which a tread is cut in the crown portion ofthe assembled tire. f r

3;,A process of retreading a tire comprising the steps 'oflbufling oiithe tread of saidtire to form a buffed crown of substantially uniformwidth, bufiing off; the tread .of 'a second tire and cutting theshoulders thereof toform 130 I portion of the assembled-tire by cuttingthe 'tire fabric a stock to bond said tread bberportion permanently 1o.

tread of a second'tire and cutting the, tire to form a multiple-plystrip of substantially uniform thickness having one side thereof formedby a ply of tire cord fabric,

applying a thin layer of uncured, gum stock and'cement around thecircumferenceof said bufied crown, assem blingsaid strip over the gumstock with said one side out of contact with said gum stock, andPlacing.the 7 assembled tire in a retread mold'so that the fahricply of said oneside engagestthe p en'pheral inner surfaceof saidmold, and subjectingthe assembly'to heat and pres- T r sure until the. gum stock isvulcanized andsaid strip is i l permanently bonded to saidcr0wn.

tire cord fabric isof substantially uniform thickness, cutting off theside walls ofsaid second tire to form a strip having a substantiallyuniform width equaltto" that of said buffed crown and of a si ze tocompletely cover said crown, turning said strip inside out, assemblingthe inside-out strip over said buffed crown withuncured gum stockdisposedbetween said crown and said strip,

the tread rubber portion of said strip facing said crown,

and engaging said gum'stock, andr'vulc anizingsaid gum the tread rubberof said crown;

6. A'process, of retreading a tire'as defined in blahn in which diagonalgrooves are formed in the,.;fabric fcap alongthe bias and ripping outthe-fabric between adjacent cuts;

reinforced; rubber tire comprising thetsteps ofjbuffing off w tially'uniform width, removing a portion of the v trea'd ofa secondw orn'pneumatic rubber-tire; and cutting the tire to form 'a multiple-plystrip 'ofgenerallyg uniform;

thickness having one side face thereof formed by a ply a of tire cordfabric and having awidth not substantially,

different from that ofsaidfbufiedcrown, the' cords'of said' ply having abias at anjangle to ;that of the, next adjacent plygapplying a thinlayer of a vulcanizable rubber adhesive compoundjaronnd thecircumference of said buffed crown, assembling said strip over ,the,layer a of said vulcanizable rubber compound with said one side face outof contact with said rubber compound; and placing the assembled "tire ina-retread mold sothat the ,1 f

fabric ply of said one side engages the; peripheral inner 7 surface ofsaid mold,'and' subjecting the assembly to heat astrip ofsubstantiallynniform thickness having a width substantially the same asthat of said buifedcrown and aflength several times said Width,assembling the cut strip over said bufied 'crownwith ;a vulca;nizabl eadhesivejcompound disposedbetweenj said crown andsaid smipfand with thefabric side of the strip providing a road-engaging surface,-placing theassembled tire in a re tread mold, and vulcanizing the adhesiveco'mpoundiin and pressure until said rubber compoundis vulcanized andsaid strip is permanently bonded tosaid crown; 7 References Cited'in thenear this patent if i UNITEDiSTATE S PATENTS 7. ,A process, ofretreading a pneumatic fabric r 588,562 T'Farme'r V q 1 ,014,912Shoemaker Ian. 16, 191 2, 1,171,449 McGiehan 'Feb; 15, 1916' .1,509,30lKearns Sept 23 1924 I 1,954,926 Fraser A r;-.;11, i1934af 2,059,982Buddiu- .1- Nov, 13,11936 2,180,650 Whitej Nev- '21,- .1939; i 2,232,4887 Smith -Feb.-, 8,194.1 2,290,624' Waite July 21; 1942 2,432,630 Purdy-V IQD8C.,'16,?1947 Hawkinson

